Starting in 1985, the BLSA health evaluation has undergone major changes to improve the medical information about research participants. Two versions of the health questionnaire have been implemented. The initial questionnaire, introduced March 1, 1991, is used on participant's first visit to determine previous health complaints and problems. The interval history questionnaire, instituted March 1, 1993, is used for all subsequent visits to document changes in health complaints and status since their previous visit and to identify the effects of symptoms on daily living. The interval history provides participant's previous responses to each items and allows the participant to indicate changes. The interval history questionnaire also included an expansion of branching questions used for positive health complaints with questions assessing effects on daily activities and emotional well being. The health evaluation also provides health screening for a number of research protocols. The unit has increased formalized handling of screening and research protocols; provided technical support to investigators in the development of research studies; and worked to minimize and/or prevent potential adverse outcomes or other problems. The staff worked with investigators on a blood pressure protocol, improved assessment of hormonal status and clean up of the historical dataset, and the collection of biopsy material. To meet research needs for studying the elderly who at times are frail, the unit is developing procedures to identify the frail individuals and a special nursing protocol with appropriate changes in visit routine. Other changes include the implementation of a physical functioning inventory to probe for mild to moderate disability in physical activity. Over the past year, we have continued as part of our quality assurance program to assess the value of the new health questionnaire for BLSA research. We continue to develop formal guidelines as needed.